A one-year study of trivalent influenza vaccines in primed and unprimed volunteers: immunogenicity, clinical reactions and protection

Abstract

Three hundred volunteers were divided into two age groups, 14-30 years and 31-60 years. Each participant was immunized intramuscularly with a subunit, whole virus or absorbed whole virus vaccine, containing A/Bangkok/1/79 (H3N2), A/Brazil/11/78 (H1N1) and B/Singapore/222/79 influenza virus. Serum haemagglutination-inhibition (HI) antibody response, protection, and reactogenicity were studied after one and two doses of the vaccines. Primary immunization induced much higher percentages of HI antibody titres greater than or equal to 100 against all three vaccine viruses and much higher geometric mean titres (GMT) in volunteers with pre-immunization titres greater than or equal to 18 as compared to those with pre-immunization titres less than 18. Secondary immunization did not result in an increase of GMTs or antibody titres greater than or equal to 100 in volunteers with pre-immunization titres less than 18. On the whole, the response to the subunit vaccine was similar to that to the other two vaccines. To influenza B/Singapore/222/79 virus the response was lowest after administration of the whole virus vaccine in the age group 31-60 years. Over 50% of the HI titres greater than or equal to 100 found after immunization in the different vaccine and age groups were still present after one year. Serologically established infections during the winter months following immunization amounted to 15% in the subunit vaccine group, 6% in the whole virus vaccine group, and 10% in the adsorbed whole virus vaccine group. Local and systemic reactions to all three vaccines were mild in nature. Local reactions after primary immunization were much less frequent following administration of the subunit vaccine as compared to the other two vaccines, especially in the younger age group. In comparison to primary immunization, after booster immunization the incidence of local reactions was higher for the subunit vaccine and lower for the adsorbed whole virus vaccine. In the age group 14-30 years the incidence of local reactions after primary as well as booster immunization was much greater in females than in males, especially when the adsorbed whole virus vaccine was used.

Gender differences in local and systemic reactions to inactivated influenza vaccine, established by a meta-analysis of fourteen independent studies

“…Some earlier papers suggested that the incidence of local or systemic reactions after influenza vaccination was higher in adult females than in adult males (3)(4)(5)(6)(7). However, two of these studies (3,5) used the influenza AfNew Jersey/76 (HIN1) swine strain, which showed unusual characteristics of reactogenicity.…”

“…However, two of these studies (3,5) used the influenza AfNew Jersey/76 (HIN1) swine strain, which showed unusual characteristics of reactogenicity. In two other reports (4,7), data on gender differences were presented as an accidental finding, and one investigation (6) had only small study groups.…”

Humoral immune response and delayed type hypersensitivity to influenza vaccine in patients with diabetes mellitus

“…With the method used, protection against influenza is thought to be associated with an HI titre of 100 for influenza A [8]. No protection threshold is known for aether-treated influenza B strains.…”

“…To accomplish protection against influenza, vaccination should induce high antibody titres against the viral haemagglutinin [8]. Simultaneously stimulated cellular immunity, though not protective, might contribute to the recovery from infections with influenza viruses [9].…”

A new approach to estimate vaccine efficacy based on immunogenicity data applied to influenza vaccines administered by the intradermal or intramuscular routes

“…The antibodies produced when an individual is exposed to HA, either naturally or through vaccination, are essential in providing immunity against influenza infection and are positively associated with clinical protection against influenza. [4][5][6][7][8][9] HA antibodies are quantified by the HI assay through measurement of HI titers. HI antibody titers therefore play a key role in the approval process of seasonal and pandemic vaccines.…”